What are the target weights for my spring-born calves during the first grazing season?
In a dairy calf-to-beef system, optimum performance is required during all stages of production. If a calf underperforms during the first grazing season, this makes it difficult to hit key target weights later in its life.
Across all the Teagasc Green Acres Calf to Beef Programme demonstration farms, a total of 991 spring-born calves – of various breeds – are present and will be brought to beef under different systems.
Bull calves account for 76% or 756 head, while heifers account for 24% or 235 head; dairy-bred males represent the largest number of calves at 510 head (51%).
This is followed by Aberdeen Angus at 257 head (26%) and Hereford at 166 head (17%). In addition, there are 58 continental-cross calves (6%) across all the farms.
All of these calves are currently at grass, grazing covers of 1,000-1,400kg DM/ha and targeting an average daily gain (ADG) of 0.7-0.8kg/day. If calves do not reach this level of performance, this can result in a longer finishing period, lighter carcasses at slaughter and additional feed costs.
Spring-born, early-maturing dairy heifers should be slaughtered before the second winter housing aged 19-21 months-of-age, aiming for a 235-250kg carcass. Therefore, an early-maturing heifer should weigh 230kg after the first grazing season.
Early spring-born, early-maturing steers have the potential to be slaughtered at the end of the second grazing season (November), achieving a carcass weight of 280kg. Early-maturing steers should have an ADG of 0.8kg/day over the first grazing season and weigh 230-240kg at housing.
However, calves (both heifers and steers) that were born later in April or May have a target at 190kg after the first grazing season, but should also have an ADG of 0.8kg/day.
Farmers operating a 24-month Friesian steer system should aim for a liveweight of 230kg – after the first grazing season – in early-to-mid November. In addition, yearling Friesian steers should have an ADG of 0.9kg/day over the second grazing period and weigh 490kg before housing for the second and final winter.
In the case of early-spring born calves – provided grass quality is high – grass intakes increase and concentrate supplementation is not required after mid-May.
These calves should remain on a grass-only diet until early September and supplemented with 1kg/day of concentrate until housing, as grass supply and quality decreases.
However, in order to reach growth targets, dairy calves – born in April/May – and going to grass later in the summer – should receive 1-2kg/day concentrate for the entire grazing period.
However, male calves targeted to be finished in a 15-month system need an average ADG of 0.9kg/day and should hit a target weight of approximately 250kg after the first grazing period. Male calves aimed to be finished – as bulls – at 19 months also need to weigh 250kg after this period.
Weighing cattle during the grazing season allows farmers to monitor animal performance and ensure that their animals are performing well. Typically, animals should be weighted at turnout, mid-season and housing.
All farms participating in the Teagasc Green Acres Calf to Beef Programme weighed their cattle prior to turnout; weighing will take place again over the coming weeks.
All farmers have also vaccinated against diseases. For spring-born calves to reach growth targets and an ADG of 0.7-0.8kg/day over the first season at grass, they must have no health issues.